设置RobotFramework的ftplibrary中，将Upload_file操作的异常改为回显错误信息。

测试中需要通过FTP通道，将数据发送给服务器，而这个上传的数据要被阻断。在结合RobotFramework测试中，安装的ftplibrary，使用upload_file操作，如果上传动作失败，会抛出异常，使Robotframework测试失败。

而其实我们就是想让他上传失败，不要抛出异常，导致测试失败。这时需要更改下ftplibrary.py。也是非常简单的，我简单记录下：

首先，下载ftplibrary安装包，下载地址：https://pypi.python.org/pypi/robotframework-ftplibrary/1.3

然后执行： Python setup.py install，将其安装。默认应该安装在\Python27\Lib\site-packages\ftplibrary.py.

打开文件后，可以看到upload_file函数的异常处理：

    def upload_file(self, localFileName, remoteFileName=None, connId='default'):
        thisConn = self.__getConnection(connId)
        outputMsg = ""
        remoteFileName_ = ""
        localFilePath = os.path.normpath(localFileName)
        if not os.path.isfile(localFilePath):
            raise FtpLibraryError("Valid file path should be provided.")
        else:
            if remoteFileName==None:
                fileTuple = os.path.split(localFileName)
                if len(fileTuple)==2:
                    remoteFileName_ = fileTuple[1]
                else:
                    remoteFileName_ = 'defaultFileName'
            else:
                remoteFileName_ = remoteFileName
            try:
                outputMsg += thisConn.storbinary("STOR " + remoteFileName_, open(localFilePath, "rb"))
            except ftplib.all_errors as e:
               raise FtpLibraryError(str(e))
        if self.printOutput:
            logger.info(outputMsg)
        return outputMsg

它引用了Python自带的ftplib库（\Python\27\Lib\ftplib.py）:

打开ftplib.py可以看到对于异常的处理：

# Exception raised when an error or invalid response is received
class Error(Exception): pass
class error_reply(Error): pass          # unexpected [123]xx reply
class error_temp(Error): pass           # 4xx errors
class error_perm(Error): pass           # 5xx errors
class error_proto(Error): pass          # response does not begin with [1-5]

# All exceptions (hopefully) that may be raised here and that aren't
# (always) programming errors on our side
all_errors = (Error, IOError, EOFError）

因为FTP上传文件被阻止后，返回的错误代码是553。所以只需要将Upload_file函数的异常处理再添加一个对“5XX”(class error_perm(Error): pass # 5xx errors)的判断即可。

下面是添加后的样子（红色是添加的异常判断）：

    def upload_file(self, localFileName, remoteFileName=None, connId='default'):
        """
        Sends file from local drive to current directory on FTP server in binary mode.
        Returns server output.
        Parameters:
        - localFileName - file name or path to a file on a local drive.
        - remoteFileName (optional) - a name or path containing name under which file should be saved.
        - connId(optional) - connection identifier. By default equals 'default'
        If remoteFileName agument is not given, local name will be used.
        Examples:
        | upload file | x.txt | connId=ftp1 |
        | upload file | D:/rfftppy/y.txt |  |
        | upload file | u.txt | uu.txt |
        | upload file | D:/rfftppy/z.txt | zz.txt |
        | upload file | D:\\rfftppy\\v.txt |  |
        """
        thisConn = self.__getConnection(connId)
        outputMsg = ""
        remoteFileName_ = ""
        localFilePath = os.path.normpath(localFileName)
        if not os.path.isfile(localFilePath):
            raise FtpLibraryError("Valid file path should be provided.")
        else:
            if remoteFileName==None:
                fileTuple = os.path.split(localFileName)
                if len(fileTuple)==2:
                    remoteFileName_ = fileTuple[1]
                else:
                    remoteFileName_ = 'defaultFileName'
            else:
                remoteFileName_ = remoteFileName
            try:
                outputMsg += thisConn.storbinary("STOR " + remoteFileName_, open(localFilePath, "rb"))
            except ftplib.error_perm as e:
               return str(e)
            except ftplib.all_errors as e:
               raise FtpLibraryError(str(e))
        if self.printOutput:
            logger.info(outputMsg)
        return outputMsg

然后再执行Robot framework测试时，就可以看到，文件被阻止了，但是测试成功，没有返回Fail：

20160316 11:07:52.446 :  INFO : 220 (vsFTPd 2.2.2)230 Login successful.
20160316 11:07:52.694 :  INFO :
${output} = 553-Requested action not taken
(by xxxx:10006)
553 END
20160316 11:07:52.698 :  INFO :
553-Requested action not taken
(by xxxx:10006)
553 END